20640658 has 8 divisors (see below), whose sum is σ = 31025520. Its totient is φ = 10298820.

The previous prime is 20640647. The next prime is 20640667. The reversal of 20640658 is 85604602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9528 + ... + 11491.

It is an arithmetic number, because the mean of its divisors is an integer number (3878190).

Almost surely, 2^20640658 is an apocalyptic number.

20640658 is a deficient number, since it is larger than the sum of its proper divisors (10384862).

20640658 is a wasteful number, since it uses less digits than its factorization.

20640658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21512.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 20640658 is about 4543.1990931501. The cubic root of 20640658 is about 274.3097089365.

The spelling of 20640658 in words is "twenty million, six hundred forty thousand, six hundred fifty-eight".